An epidemiologic approach to peer review resulting in validated criteria for assessing the quality of medical care is proposed. This includes not only the traditional study of hospitalization, but also those factors preceeding hospitalization, such as primary prevention (screening), secondary prevention (case-finding) and office management, and those following discharge, including tertiary prevention (rehabilitation). We propose to apply this model to the study of the cost and quality of medical care in the region surrounding Charlottesville, Va., and compare the results in this area to areas in the Shenandoah Valley and Roanoke, Va., where peer review and validated criteria are not in use. The data base developed would identify inefficiencies within the health care system and determine the extent to which the use of peer review and validated criteria had improved the quality of care and decreased the cost of health care. The proposal also includes in intensive study of cost control of expensive procedures to investigate their value and indications for their use. Pertinent educational programs would be conducted through local medical societies to teach practitioners the indications for use of expensive procedures and correct inefficiencies in patterns of health care delivery. The project is likely to have a significant effect on utilization of health care facilities in the region and in addition would provide a national model for the use of validated criteria in peer review programs.